How do you check inverter compatibility before buying a rack battery?

Direct answer: Do not rely on that statement. Compare the battery’s voltage window and current limits with the inverter’s, confirm the communication protocol and cable, get written confirmation naming your inverter model and firmware, and pilot one unit before bulk. A brand list on a web page is not an approval.

Collect the battery side first. The PM-LV51100-3U lists 51.2V, 58.4V maximum charge, 40V cut-off, 100A maximum continuous charge and discharge, RS485 / RS232 / CAN bus, manual DIP-switch addressing (automatic DIP optional) and up to 64 modules in parallel. The PM-LV51200-5U lists RS485 and CAN bus and 16–32 modules in parallel. These are the numbers the inverter has to work with.

Then the inverter side, from its manual: the accepted battery voltage range, the maximum charge and discharge current it can request, how it selects a battery profile (a named protocol or user-defined voltages), which communication ports and protocols it supports, and whether it publishes an approved-battery list. Note the firmware version, since protocol support can change with updates.

Compare them. The inverter’s charge voltage must not exceed the battery’s maximum, its low-voltage cut-off must sit above the battery’s cut-off, and the combined charge current across all modules must respect each module’s 100A limit. Make sure the inverter and the battery use the same protocol (RS485 or CAN) and that the cable pinout matches. Mismatches usually show as a “communication lost” alarm or a battery with no state-of-charge reading.

The Redway pages list compatible inverter brands, but not models, firmware or protocol versions, and the PowerAll page describes an integrated inverter, which removes this question for that product. Ask Redway, in writing, to confirm your exact inverter model and firmware, the protocol and DIP setting to use, and the inverter settings it recommends. If it cannot, treat that as a risk.

Pilot one module before bulk: wire it, set the profile, run a full charge and discharge, and check that voltage, current, state of charge and alarms appear correctly on the inverter. Keep the settings and cable details on file. If something fails, our post on paralleling PM-LV rack batteries of mixed age covers a related set of checks once you add units.